Absolute calibration of the distance scale using classical pulsating stars in the Gaia era
Dr. Anupam Bhardwaj
INAF-Osservatorio Astronomico di Capodimonte, Napoli, Italy
Date & Time :
Classical pulsating stars such as Cepheid and RR Lyrae variables are the most sensitive probes for precision stellar astrophysics and extragalactic distance measurements. These stellar standard candles obey well-defined period-luminosity relations which provide an absolute calibration of the first rung of the cosmic distance ladder leading to an increasingly accurate and precise local determination of the Hubble constant. Given the ongoing Hubble tension, Cepheid-independent primary calibrations are being used to not only measure the Hubble constant independently but also to better understand possible systematic uncertainties in the local measurements. I will present the recent progress in the absolute calibration of period-luminosity relations of Classical Cepheid, RR Lyrae, and Type II Cepheid variables in the Gaia era. I will also discuss our ongoing theoretical and observational efforts to quantify metallicity effects and other residual systematics in the use of classical pulsators as primary standard candles in the upcoming era of extremely large telescopes.
About Speaker :
Dr. Anupam Bhardwaj is a Marie Sklodowska-Curie post-doctoral fellow at the INAF - Osservatorio Astronomico di Capodimonte Napoli, Italy. His research interest are in Variable stars, Stellar evolution and pulsation, extragalactic distance scale, Resolved stellar populations in nearby galaxies, etc. This seminar is a part of the activities "75 years of India's Independence: Azadi ka Amrit Mahotsav" at ARIES.